Multi-modulation radio communications

A modem comprising:

• a multi-modulation modem comprising:
• a modulator including a modulation selector unit, wherein the modulator modulates signals using a plurality of modulations, wherein the modulation selector unit selects respective ones of the plurality of modulations to modulate the signals on a burst-by-burst basis;
• and
• a demodulator for demodulating the signals using a plurality of modulation modes, wherein said modulation selector unit comprises:
• a byte to symbol converter;
• a burst formatter coupled to the byte to symbol converter for formatting said signals into bursts;
• and a constellation lookup unit coupled to the burst formatter for mapping respective signals into respective ones of a plurality of constellations, wherein each of the plurality of constellations corresponds to a respective one of said plurality of modulations;
• a transmit buffer interface;
• a scrambler coupled to a transmit buffer interface;
• an encoder coupled to the scrambler;
• said modulation selector unit coupled to the encoder;
• a pulse shaper coupled to said modulation selector unit;
• a halfband filter coupled to the pulse shaper;
• a ramper coupled to the halfband filter;
• a linearizer coupled to the ramper;
• an intermediate frequency modulator coupled to the linearizer;
• and
• a sync distortion compensation filter coupled to the intermediate frequency modulator.

A modem comprising:

• a multi-modulation modem comprising:
• a modulator including a modulation selector unit, wherein the modulator modulates signals using a plurality of modulations, wherein the modulation selector unit selects respective ones of the plurality of modulations to modulate the signals on a burst-by-burst basis;
• and
• a demodulator for demodulating the signals using a plurality of modulation modes, wherein said demodulator includes an acquisition section and a tracking section coupled to the acquisition section, and the tracking section demodulates received signals having been modulated with said plurality of modulations;
• wherein said tracking section comprises:
• an equalizer and phase rotator unit, wherein the equalizer and phase rotator unit minimizes intersymbol interference;
• a multi-modulation slicer coupled to said equalizer and phase rotator unit, wherein the multi-modulation slicer maps said signals into one of a plurality of constellations, wherein each of the plurality of constellations is associated with one of said plurality of modulations;
• and a carrier recovery loop coupled to said multi-modulation slicer and said equalizer and phase rotator unit, wherein the carrier recovery loop recovers suppressed carrier signals using one or more of said plurality of modulations.

A method of modulation comprising:

• receiving signals into a modulator;
• converting the signals to symbols;
• formatting the symbols into bursts;
• mapping the bursts into respective ones of a plurality of constellations, wherein each of the plurality of constellations corresponds to a respective one of a plurality of modulations;
• modulating the bursts using respective ones of the plurality of modulations;
• scrambling said signals prior to said converting;
• encoding said signals prior to said converting;
• interpolating said bursts after said mapping and prior to said modulating;
• applying a ramp to said bursts prior to said modulating;
• compensating for non-linear distortion in said bursts prior to said modulating;
• and
• compensating for sinc distortion after said modulating.

A radio comprising:

• a multi-modulation modem, wherein the multi-modulation modem comprises:
• a modulator that modulates signals using a plurality of modulations;
• and
• a demodulator that demodulates received signals having been modulated using said plurality of modulations, wherein the demodulator comprises:
• an acquisition section, wherein the acquisition section comprises:
• a precorrelation filter, and a burst detector;
• and a parameter estimator unit coupled to the precorrelation filter;
• and
• a tracking section, wherein the tracking section comprises:
• an automatic gain control;
• an equalizer and phase rotator unit coupled to the automatic gain control;
• a multi-modulation slicer coupled to the equalizer and phase rotator unit;
• and a carrier recovery loop coupled to the multi-modulation slicer and the equalizer and phase rotator unit, wherein the multi-modulation slicer maps said received signals to a respective one of a plurality of constellations, and each of said plurality of constellations corresponds to respective ones of said plurality of modulations;
• a frequency converter coupled to the multi-modulation modem for converting the signals to a radio frequency;
• and
• a transceiver unit including an antennae coupled to the frequency converter for transmitting the signals over a radio communications link.

A modem comprising:

• a multi-modulation modem comprising:
• a modulator including a modulation selector unit, wherein the modulator modulates signals using a plurality of modulations, wherein the modulation selector unit selects respective ones of a plurality of modulations to modulate the signals;
• and
• a demodulator for demodulating the signals using the plurality of modulation modes;
• the modulation selector unit comprising:
• a byte to symbol converter;
• a burst formatter coupled to the byte to symbol converter for formatting said signals into bursts;
• and
• a constellation lookup unit coupled to the burst formatter for mapping respective signals into respective ones of a plurality of constellations, wherein each of the plurality of constellations corresponds to a respective one of said plurality of modulations;
• a transmit buffer interface;
• a scrambler coupled to a transmit buffer interface;
• an encoder coupled to the scrambler;
• said modulation selector unit coupled to the encoder;
• a pulse shaper coupled to said modulation selector unit;
• a halfband filter coupled to the pulse shaper;
• a ramper coupled to the halfband filter;
• a linearizer coupled to the ramper;
• an intermediate frequency modulator coupled to the linearizer;
• and
• a sync distortion compensation filter coupled to the intermediate frequency modulator.

A modem comprising:

• a multi-modulation modem comprising:
• a modulator including a modulation selector unit, wherein the modulator modulates signals using a plurality of modulations, wherein the modulation selector unit selects respective ones of the plurality of modulations to modulate the signals;
• and
• a demodulator for demodulating the signals using a plurality of modulation modes, wherein the demodulator includes an acquisition selection and a tracking section coupled to the acquisition section, wherein the tracking section demodulates received signals having been modulated with said plurality of modulations;
• said tracking section includes:
• an equalizer and phase rotator unit, wherein the equalizer and phase rotator unit minimizes intersymbol interference;
• a multi-modulation slicer coupled to said equalizer and phase rotator unit, wherein the multi-modulation slicer maps said signals into one of a plurality of constellations, wherein each of the plurality of constellations is associated with one of said plurality of modulations;
• and
• a carrier recovery loop coupled to said multi-modulation slicer and said equalizer and phase rotator unit, wherein the carrier recovery loop recovers suppressed carrier signals using one or more of said plurality of modulations;
• a symbol to byte converter coupled to said multi-modulation slicer of said tracking section;
• a decoder coupled to said symbol to byte converter;
• a descrambler coupled to the decoder;
• and
• an output buffer coupled to the descrambler.

A method of modulation comprising:

• receiving signals into a modulator;
• scrambling and encoding the signals;
• converting the signals to symbols;
• formatting the symbols into bursts;
• mapping the bursts into respective ones of a plurality of constellations, wherein each of the plurality of constellations corresponds to a respective one of a plurality of modulations;
• interpolating said bursts and applying a ramp to said bursts;
• compensating for non-linear distortion in said bursts;
• modulating the bursts using respective ones of the plurality of modulations;
• and
• compensating for sync distortion.